rf_soapy: print warning when using the Lime with shorter sample rates

the Lime has better performance when using the default LTE sample
rates due to filterering being done in the LMS RF chip.

Print a warning when using the Lime with the non-default LTE rates.

lib/src/phy/rf/rf_soapy_imp.c

@@ -310,6 +310,12 @@ int rf_soapy_open_multi(char* args, void** h, uint32_t num_requested_channels)
     printf("\n");
   }
 
+  // With the Lime we are better off using LTE sample rates
+  if (strcmp(devname, "Lime") && srslte_symbol_size_is_standard() == false) {
+    printf("\033[0;31mConsider using LTE sample rates for better RF performance.\nEither compile with "
+           "\'-DUSE_LTE_RATES=True\' or start srsENB or srsUE with \'--expert.lte_sample_rates=true\'\033[0m\n");
+  }
+
   // Select Soapy device by id
   int dev_id = 0;
   if (args != NULL) {